Display PostScript: Difference between revisions

Revision as of 08:52, 16 May 2025

Latest revision as of 10:03, 14 July 2025

(3 intermediate revisions by 2 users not shown)

Line 1:

{{Short description|2D graphics engine}}

{{Multiple issues|

{{no footnotes|date=August 2012}}

Line 6 ⟶ 7:

'''Display PostScript''' (or '''DPS''') is a [[2D computer graphics|2D graphics engine]] system for computers that uses the [[PostScript]] (PS) imaging model and language to generate on-screen graphics. PS was originally developed for [[computer printing]], to which DPS adds a number of features intended to ease working with [[bitmap]]ped displays and improve performance of some common tasks.

Early versions of PostScript display systems were developed at [[Adobe Systems]]. During development of the [[NeXT]] computers, NeXT and Adobe collaborated to produce the official DPS system, which was released in 1987. NeXT used DPS throughout its history, while versions from Adobe were popular on Unix workstations for a time during the 1980s and 1990s. The [[SunOS]] [[NeWS]] window system used DPS from the end of the 1980s into the 1990s.

== Design ==

Line 24 ⟶ 25:

== History ==

[[NeXT]] in September 1987 became the first company to license Display Postscript.{{r|lach19880118}} The developers of [[NeXT]] wrote a completely new windowing engine to take full advantage of NeXT's [[object-oriented operating system]]. A number of commands were added to DPS to create the windows and to react to events, similar to but simpler than [[NeWS]]. The single API made programming at higher levels much easier and made NeXT one of the few systems to extensively use DPS. The user-space windowing system library [[NeXTSTEP]] used PostScript to draw items like titlebars and scrollers. This, in turn, made extensive use of <code>pswrap</code>s, which were in turn wrapped in objects and presented to the programmer in object form.

[[Digital Equipment Corporation]] in early 1988 licensed Display PostScript for [[DECwindows]]. Adobe said that it hoped that [[IBM]] and [[Microsoft]], for [[OS/2]] [[Presentation Manager]], and [[Apple Computer]] would also use the technology.<ref name="lach19880118">{{Cite magazine |last=Lach |first=Eric |date=18 January 1988 |title=Adobe Urges Apple, IBM To use Display PostScript |url=https://books.google.com/books?id=Dz8EAAAAMBAJ&pg=PA5#v=onepage&q&f=false |access-date=2025-05-25 |magazine=[[InfoWorld]] |page=5 |volume=10 |issue=3}}</ref>

The developers of [[NeXT]] wrote a completely new windowing engine to take full advantage of NeXT's [[object-oriented operating system]]. A number of commands were added to DPS to create the windows and to react to events, similar to but simpler than [[NeWS]]. The single API made programming at higher levels much easier and made NeXT one of the few systems to extensively use DPS. The user-space windowing system library [[NeXTSTEP]] used PostScript to draw items like titlebars and scrollers. This, in turn, made extensive use of <code>pswrap</code>s, which were in turn wrapped in objects and presented to the programmer in object form.

In November 1993 Sun Microsystems shipped [[OpenWindows]] 3.3, which dropped the support for [[NeWS]] and its non-standard extensions to PostScript, replacing it with DPS.

== Modern derivatives ==

[[AppleAfter acquiring NeXT, Inc.|Apple]]'s [[macOS|Mac OS X]] operating system uses a central window server (created entirely by Apple) that caches window graphics as bitmaps, instead of storing and executing PostScript code.{{Citation needed|date=February 2018}} A graphics library called [[Quartz 2D]] provides PostScript-style imaging using the PDF rendering model (a subset, plus tweaks, of the PostScript model), but this is used by application frameworks—there is no PostScript present in the Mac OS X window server. Apple chose to use this model for a variety of reasons, including the avoidance of licensing fees for DPS and more efficient support of legacy [[Carbon (API)|Carbon]] and [[Classic (Mac OS X)|Classic]] code; [[QuickDraw]]-based applications use bitmapped drawing exclusively.

== See also ==

* [[NeWS]], a similar conceptwindow system that used PSthe forPostScript displaygraphic model, but includedwith aextensions completefor windowingconcurrency, systemevents and OOP

* [[PostScript Standard Encoding]] (PostScript character set)

* [[NeXT character set]]

Line 58 ⟶ 62:

* [https://web.archive.org/web/20060603154639/http://partners.adobe.com/public/developer/en/ps/psrefman.pdf PostScript Language Reference, Second Edition]

* [https://web.archive.org/web/20080515120658/http://partners.adobe.com/public/developer/ps/sdk/index_archive.html#dps Display PostScript reference documents]

* [https://www.donhopkins.com/home/archive/NeWS/leffler.text.txt Comparison between Display PostScript and NeWS]

{{XWinSys}}